a = 1
a++
console.log(a)
// 2
b = 1
console.log(++b)
// 2

function Person(name, age, sex) {
  var a = 0
  this.name = name
  this.age = age
  this.sex = sex
  function sss() {
    a++
    console.log(a)
  }
  this.say = sss
}
var zs = new Person()
zs.say()
zs.say()
var ls = new Person()
ls.say()
// 1
// 2
// 1
